Kiln for the burning of cement



March 29, 1927. C0 NASKE 1,622,337

'KILN FOR THE BURNING OF CEMENT Filed Feb. 7, 1925 Inventnr: C, NQ/SIKQ/ 57 wa s.

Patented Mar. 29,1927. I

UNITED STATES cam. fNAsKE, or nnnLm-cnnnnorrnnnune, GERMANY.-

KILN' r03 THE Bunmn or CEMENT.

Application filed February 7, 1925, Serial No. 7,629, and in Germany January 8, 1 924.

This invention has reference to automatic upright kilns or shaft furnaces for the burning of cement, and it is intended to generally improve the utilization of the heat and to facilitate the operation and increase the output of available product. In the previous art means have been disclosed for the purpose of injecting the finely ground material under treatment together with the fuel, particularly gas,-either in the horizontal direction into a substantially horizontal chamber or vertically downwards into anupright chamber. In this operation the intensity of the flanrie is so adjusted that the particles of the material to be burnt-are in-' jected into one section of a bipartite heat accumulator or regenerator, where they become deposited and, together with the waste 7 gases, yield the heat still contained therein to the heat accumulator or regenerator. After one section of such regenerator or the like, as disclosed in the previous art, has

been heated in' the manner described, the other section thereof is heated after the reversal-of two rotating valves or dampers.

while the air of combustion is now aspirated perature, and subsequentlyin consequence of increasing cooling of the particular section of the regenerator the heating gradually .diminishes, so that the utilization of the waste heat is gradually impaired. It therefore becomes necessary to constantly change the admission'of fuel, so that it will be practicallV impossible to obtain a thoroughly uni formly burnt kind of goods by means of the previous apparatus, though this is a point of chief importance not only in the case of cement, but also with all other kinds of material to be calcined. Besides. the highly heated burning chamber is only incompletely utilized for the preheating of the air of combustion: nor can it be used for the frequently desired subsequent sintering of the material to be calcined.

The invention has for its ob ect to obviate andovercome the difficulties referred to in connection with kilns or shaft furnaces,

and in view thereof the material and the fuel .are introduced at the lower portion of the kiln, so that the flame is upwardly directed. The invention will be more fully zontal section on. the line 33 of Figure 1, and Figure 4 is a horizontal section on the line 4-4 ofFigure 2. v

The shaft of the kiln is indicated at a, and b is the dust chamber communicating with the heating channels a, c extending backand forth, as shown, d and e are the containersfor coal dust and crude meal of the material respectively, f is a high: pressure fan or blower; g is the burning nozzle, h is a short tube for the admission of the preheated air of combustioninto the calcining shaft, 2' are chutes along which the burnt material is adapted to slide down into the delivery device k. Then, Zis the suction pipe, m and n are the pressure tubes of the fan, or blower f; -0 is 'aself-acting valve or damper, p is another blower or fan, 9 indicates another dust chamber, 1' and s are two conveyor screws, t'is a dredger or the like, u is a closing slide, 1) are two drying'drums for the crude material, w is the chimney-,4 is a conveyor chute for the burnt or calcined material, is a low pressure fan or blower, and a is the fresh air damper or valve.

- The members a, b and c are jacketed and their interior walls at the points of the high-' est generation of heat consist of highly refractive clay or bricks, at the other points of ordinary chamotte or clay, while the-outer walls are made of well insulated brick masonry or concrete masonry. Between the two walls there is a space for the circulation of the air. of combustion. The'a-ir enters through the adjustable valve or damper a by the action of the chimney; it flows through the space between the walls and is thereby highly heated. The air is finally ATENT OFFICE, I

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ins

portion of the air of combustion is sucked In orperature of this small portionof the air'of combustion below a certain limit.

The mode of operation of the apparatus issubstantially as follows The particles of material (arrows 1) having been carried up and calcined up by the flame have thereby acquired a higher specific gravity and drop. down along the walls of the shaft a (arrows 2) and proceed by way of the chutes z to the delivery device, or gate is, adapted to prevent the entrance of outer air into the shaft. The particles of calcined material drop from the gate is into a shaking chute or channel at or into a similar device whence they are carried away for further treatment. The particles of material, however, which have not been completely calcined are carried by the suction of the chimney into the dust chamber 7) (arrows 3) where they drop to the bottom, and become accumulated until their weight 'is suflicient to open the valve or closure 0 sufliciently to allow them of being acted upon by the fan or blower p by means of which .they are-blown into the second dust chains ber g. In this chamber they are caused to settle, preferably by electric means, and are collected and are continuously conducted to the crude meal container 6 by the conveyor screws 1', s and the dredger t, and may then be burnt over,again. By this means it is not only possible to avoid all losses of dust of material, but there is the further advan tage that the finest agglomerated.

For the purpose of recovering the waste heat of the finished product a pressure pipe n is branched off from the pressure pipe m, said branch pipe at being adapted to lead an adjustable fraction of the air of combustion sucked in-by the pipe Z, through the glowing and completely'calcined particles and to extract the excess of heat therefrom. This highly heated portion of the air passes under the combined aspirating action of the chim-,

ney and of the nozzle into the shaft 5. The

' regulation is effected by means of the damper of a temperature exceeding the temperature necessary for keeping up thechimney draft, the gases, as appears from the drawing may beled throughthe drums/v where the crude material is dried.

For the occasional cleaning of the system deviation from the principles and from the particles of'dust can be charging means communicating with the botof channels a, which is likely to become necessary, a low pressure ventilator or fan y is provided which, with the slide or damper u in the closed position and with the high pressure blower f out ofioperation, and with the the accumulated remnants of flue dust back from the channels 0 and'D and into the chamber 6 where they are aspirated by the blower p and are thereby carried into the second dust chamber 9.

The entire arrangement of kiln with accessories operates in a perfectly automatic manner, after it has been once adjusted for a certain quantity of fuel found y experience to be the proper amount, and ith substantially unchanging size. of flame and degrees of temperature of the heat of combustion. It should also be mentioned that the kiln or furnace may also be provided, with inclined shafts instead of with a vertical shaft, as

herein shown by way of exemplifica'tion only,

and it should be understood that other changes and modifications may occur in ac-v 'valve or damper 0 opened, is adapted to blow cordance with the particular requirements of the varying conditions of application of the invention and to'suit the convenience of the operator, such changes not constituting any scope of my invention, as defined in the claims hereunto appended. 1

I claim 1., Ina calcining kiln for cement and the like a burning and calcining shaft, a single tom portion below the said fuel-air-and-material introducing means and a settling chamber communicating with thetop portion of the shaft. 7

2. In a calcining kiln for cement and the like a burning and calcining shaft, chutes for the removal of the calcined cement material below said shaft, .a'highpressure blower,

shaft for the admission of solid cement material in finely divided condition, fuel and air of combustion into said bottom portion, a. branch conduit on the compression side of said blowercommunicating with the said chutes, discharging means communicating with said chutes, and a settling chamber communicating with the top portion of the shaft, and substantially adjacent therewith.

3. Ina calcining kiln for cement and the like a burning andcalcining shaft, a bi hpressure blower and a tube, said tube being 7 adapted for the introduction of solid cement y I conduit for introducing solid cement mate- 7 means connected with said blower and communlcating with the bottom portion of said material to the shaft chutes for the removal of calcined cement material from the shaft, said chutes being arranged below the'shaft and communicating with the bottom portion thereof, chutes connecting said tube to the compression side of said blower, an air-introducing suction pipe on the blower and a delivery pipe on the blower connected to the bottom of the shaft and receiving means 0 for fuel and solid cement material on said delivery pipe.

4; In a calcining kiln for cement and the like a jacketed burning and calcining shaft, a F jacketed settling chamber, communicating with the top portion thereof, air admitting means for said jackets, and communicatm means between the jackets of the shaft and o the chamber, air heating passages below the shaft and the chamber and communicating with the jackets and with the bottom of the 20 shaft means adapted to deliver finely divided material under treatment and fuel into the bottom portion of. the calcining shaft :1 high ressure blower communicating with said deivering means and with an air supply, and 25 discharging means in the bottom portion of said shaft.

In testimony whereof I have signed my name to this specification.

CARL NASKE. 

